Carburetor



0. H. ENSIGN July 23, 1929.

CARBURETOR Filed April 17, 1922 Z'Sheets-Sheet l :1:"E:n 2"u:== h 0 0.H. ENSIGN July 23, 1929.

CARBURETOR Filed April 17, 192 2 2 Sheets-Sheet 2 fwerzfor 0r L'ZZeafi'nwyn L/UWM ,M

Patented July 23, 1929.

UNITED STATES PATENT OFFICE.

ORVILLE H. ENSIGN, OF PASADENA, CALIFORNIA, ASSIGNOR TO EN SIGN CARBURE-TOR COMPANY, OF LOS ANGELES, CALIFORNIA, A CORPORATION OF CALIFORNIA.

CARBURETOR.

Application filed April 17, 1922. Serial No. 554,027.

An object of this invention is to make an improved completeself-contained economial carburetor of moderate cost adapted to producea more perfect mixture at all speeds.

Anobject is to provide means whereby an internal combustion engineequipped with the Venturi type of carouretor can be started readily incold or ordinary weather and can immediately be adjusted from apointconvenient to the operator to develop smooth and economical operationfrom idling up to full power and will be free from excessive consumptionof fuel at the higher speeds, when set to run smoothly at low or anyother speed.

An object is to utilize the startin device above referred to as a meansfor ma ring adjustments of capacity or as a means for making it possibleto abandon the adjustment of the metering orifice. and to use thisdevice for adjustment of motor mixture proportions on factory run ofequipment.

An object is to provide a novel carburetor that is more easily adaptableto different size motors.

Other objects, advantages and features of invention may appear from theaccompanying drawings, the subjoined detail description and the appendedclaims.

The invention may be applied in various forms and will be mainlyillustrated as applied in av vertical type.

The accompanying drawings illustrate the invention.

Figure 1 is a vertical section of a carburetcr showing the inventionapplied in a simple fc m with parts in full load running position.Dotted lines indicate a starting po sition.

Fig. 2 is an enlarged fragmental detail of the V enturi throat and fuelsupply means shown in Fig. 1. with the fuel in the positionit takes whenin idling operation.

Fig. 3 is a fragmental section through the throat of the venturi in Fig.1, showing a d fferent for-m of accelerating well from that shown inFig. 1.

F ig. l; is a plan of the construction shown in Fig. 3.

Fig. 5 is a side elevation of a form of the carburetor showing the partsin engine start-- ing position.

Fig. 6 is a vertical section on line m, Fig. 5, of the upper piece ofthe carburetor through the fuel adjusting means.-

Fig. 7 is a horizontal section on line in, Figs. 5 and 6. r

Fig. 8 is a plan view of the lower member of the carburetor showing theaccelerating chamber and starting levers.

Fig. 9 is a diagrammatic cross section through the throat of ahorizontal venturi indicating delivery of liquid fuel to such throat inaccordance with the principles of this invention.

The vertical type of carburetor shown in Figs. 1-8 is of such characterthat it may be made of two main pieces A, B, and certain necessaryauxiliary parts for the purpose of operation and adjustment, and themain pieces are shown oined together at the point of maximum airvelocity through the carburetor. The piece A may be a single castingcomprising and containing a constant level fuel chamber 1, riser 2 anddrop pipe 3; the upper expanding portion 4 of the venturi, a throttlebarrel 5 and a flange a by which said piece A may be attached to themanifold of an internal combustion engine, not shown.

Piece B is conveniently made to include the air intake and theaccelerating well and the fuel jets for delivering fuel to the venturi.

Located in the wall between the constant level fuel chamber 1 and theexpanding portion 4 of the venturi, and extended to the throttle 5, arethe various elements which constitute the means for delivery of fuelfrom the constant level chamber to the throat 6 of the venturi; and insuch wall are also located the means for adjustment thereof. The meansfor delivering fuel to the throat 6 comprises a fuel orifice 7 thatdelivers fuel to the fuel riser 2 which is adapted to furnish fuel byoverflow at 8 into the drop pipe 3 that forms the upper portion of afuel passage the lower end of which is extended by the tube 9 whichforms a seal in a sealing pocket 10 formed in the bottom of a reservoirthat in Figs. 1, 2 and 8 is cut in the upper end of piece B and suchreservoir is shown as a circular groove that lies in an approximatelyhorizontal plane around the Venturi throat. Said reservoir constitutes aportion of the fuel passage between the overflow 8 and the throat of theventuri where the fuel is ejected or delivered into the main air streamby means of the ports 12 opening from the reservoir into said throataround the periphery of the throat.

The piece B is provided with an air intake V 13 that opens into thespherical inlet chamber 14, from which a gradual approach 15 extendsupwardly to the Venturi throat 6. From this throat 6 the walls of theventuri in piece A gradually expand through the portion 4 joining thethrottle barrel 5 at the intersection 16. The throttle barrel isprovided with a throttle 17 mounted on a shaft 18.

The piece A is provided with a boss 19 through which a bore 20 extendsinto the throttle barrel below the throttle. Into the inner end of bore20 there is fitted a bushing 21 into which is soldered a by-pass idlingtube 22 that extends through the center of the Venturi throat andconnects to a sump 23 and that is provided therein with a hole 24 forallowing liquid and air to be drawn from the sump into said tube. Anupwardly inclined idling fuel passage 25 extends through the walls ofthe bushing 21 and the tube 22 into the tube, thus providing a passagefrom the hole 24 at the lower end of the tube 22 through said tube andthe inclined passage 25 to the space above the throttle. Said bushing 21is further provided with a vent 27 which opens from said by-pass tube 22and the idling jet hole 25 into the bore 20 and thereby communicateswith the riser above the overflow, and an adjusting needle valve 28 isprovided for regulating the opening through the vent 27.

The fuel riser 2 is extended upwardly to join the bore 20 so that thedepression arising at the upper end of the idling fuel passage 25 atidling may be controlled by the valve 28 to applysuitable depressionat'the top of the riser to supply suflicient fuel for idling, the flowof which is controlled by the valve 28.

The depression arising at 25 is applied to the tube 22 and is bledaccording to the degree of opening of the valve 28. However. thedepression arising during idling at 25 and applied to the hole 24through the tube 22 is sufficient at any opening of the valve 28 to drawfuel from the sump 23 and deliver the samebeyond the throttle from theidling fuel passage 25.

There is also provided an unregulated vent 29 acting as an air bleed andwhich connects the top of the riser 2 and the throttle barrel underneaththe throttle, to modify the depression at the top of the riser, whichdepression is produced under load by the Venturi throat through themedium of the fuel passage or during idling by the high vacuum above thethrottle applied through the inclined passage 25. One function of thebypass tube 22 is to first pick up any fuel which drops from the fueljet holes 12 to. the sump 23 and to deliver such fuel above the throttlewhen starting and when idling. One function of the jet 25 is to providesuction at the top of the fuel riser 2 when idling, to lift the fuelfrom the constant. fuel level 30 over the over-flow point 8, which ispreferably located some distance above the constant fuel level 30 toprevent leakage, thus providing means for adjusting the idling mixtureof the operating carburetor by utilizing the suction beyond the throttlemodified by means of the fixed vent 29 and the adjustable vent 27 forcontrolling idling mixture.

The constant level fuel chamber 1 is provided with a float 31 connectedto a float lever 32 which engages a float valve 33 to con trol the flowof fuel and to practically main tain the fuel at the constant level 30.

For purposes of starting the engine, and for other uses to bedescribedlater, a pear shaped plug 34 concentric with the bore of the throat ofthe venturi 6, is provided and arranged to slide upon the tube 22. Saidplug 34 is connected through the link 35, pins 36, lever arm 37 andshaft 38 to the outside lever 39 where it may be connected to a wire notshown for operating the plug to raise and lower the same to reduce theopening through the throat 6 forpurpose of starting and controlling themixture for a short time after starting a cold motor.

This is brought about by moving the outside lever 39 by such wire whichmay be extended to a point convenient to the operator. Raising andlowering the lever 39 raises and lowers the plug 34 for the purposeabove described.

The inside lever 37 is adapted to engage an adjusting screw 46 fordetermining the lowest position of the plug 34.

A top screw 47 provides adjustment of the upper position of the plug sothat the plug may not close the throat 6. For a predetermined engine anda predetermined work the form in Fig. 1 represents a fixed fuel orificetype of carburetor, but it is generally desired that the fuel orifice beadjustable, in the form shown in Figs. 5, 6 and 7.

In Figs. 5, 6 and 7 the opening 48 constitutes a connection between theconstant level fuel chamber and the approach 49 to the fuel orifice 7 inthis type. This orifice 48 is drilled through from a hole 50 which isplugged with a screw 50.

The approach 49 and the fuel orifice 7 are intersected by the drilledhole 51 into which is fitted the fuel valve 52 operated by screw 53.

In Figs. 1', 2 and 8 the reservoir 11 of .the fuel passage is shown as aplain groove cut in the top of the piece B and covered by piece A, anddeepen ed at 10 to form the seal pocket. At one side of the seal pocket10 is an obstruction or dam 54 inserted in said groove so as to preventthe flow of fuel and air in any but one direction around the groove,thus to make the delivery of air with the fuel through holes 12,progressive.

Figs. 3 and 4show an alternative form of accelerating chamber in whichthe fuel passage is extended to surround the Venturi throat in the formof an outer covered groove into which the fuel is delivered from theSeal pocket, This is also obstructed by a dam 54' so that the fuel canflow only one way around the groove. This outer annular grooveprogressively delivers fuel and air at the bottom into the inner annulargroove or reservoir 56 of the fuel passage through the holes 57.

The fuel and air flowing from the seal pocket 10 will flow around theouter groove and through the holes 57; and the air will bubble acrossthe groove 56 to the holes 12 which are opposite the supply holes 57 andsurround the plug 34 and discharge from the top of the reservoir intothe Venturi throat. Said air will not only carry the fuel from thegroove 55 but will carry fuel gradually from the groove 56 so that thereis a progressive delivery of fuel through the combination of the grooves55 and 56, and so that the fuel will be delivered less rapidly than withthe form shown in Fig. 1.

In the form of accelerating chamber shown in Figs. 1 and 2 there may beprovided an additional air passage 59 extending downwardly from a pointslightly above the Venturi throat into the top of the groove 11.

And there may also be provided air vents extending from the top of thereservoir 11 to the discharge end of the jet holes 12, so that air willat all times join the fuel in the holes 12 at the discharge end of saidholes and will pass from the holes 12 with the fuel.

- thus breaking the surface tension and insuring atomization at all airvelocities through the venturi, and preventing a too rapid emptying ofthe accelerating chamber.

Said passages are formed by drilling from the outside of the carburetorcasing and the open ends of these passages are closed by plugs 61. Thecover 62 to the constant level fuel chamber 1 is provided with air vent63 to apply atmospheric pressure upon the surface of fuel 30. Themachine screws 64 are provided for the attachment of piece A to piece B.

The operation of this carburetor may be described as follows:

With the form shown in. Fig. 1, the fuel orifice 7 is of fixeddimensions for equipment at a factory where with accurately builtengines it is possible to develop the right size of this fuel orifice 7for such engines so that satisfactory results will be attained withoutfurther adjustment means except for idling.

For miscellaneous use on different engines it is necessary to providemeans for making individual adjustments and this is shown in Figs. 5, 6and 7.

Assuming that the fuel orifice has been properly adjusted for full loadoperation, and the engine is cranked when cold, the operator will firstmove the arm 39 upwardly and thereby cause the plug 34 to take thestarting position shown in dotted lines, Figs. 1 and 5, to cause a highvacuum to be produced above the throat of the venturi which in turncauses the fuel to flow in large quantities through the fuel orifice 7the riser 2, drop pipe 3, and res ervoir 11, and to issue from the jetholes 12 to the main air stream below the constant fuel I level 30 at ahigh velocity and to be thorough- Under load operation the depression atthe I throat'6 of the venturi, which is the greatest depression belowthe throttle, will he communicated through the jet holes 12, thereservoir 11, and drop pipe 3 of the fuel passage, to the surface of thefuel in the riser, and such depression will cause the fuel to flowthrough the fuel orifice 7 and over the top 8 of the riser, and willcause air or mixture to be drawn through the fixed vent 29 and such airand fuel will flow together downwardly through the seal tube 9, andsealing pocket 10, and into the reservoir 11. The air and fuel issuingtogether through the jet holes 12 into the venturi will atomize the fuelin all loads or velocity of air through the venturi, except for extremelow idling speed.

lVhen the engine is idling the depression at the throat 6 of the venturiis not suflicient to lift the necessary amount of fuel for operating theengine over the difference of elevation between the normal fuel level 30and the point of overflow 8.

Upon closing the throttle to allow the engine to idle, there is produceda considerable depression above the throttle, generally of the order ofeight pounds to the square inch, which causes air to be drawn from theair intake 13 through the hole 24 into the bore 26 of the by-pass tube22 and thence through the inclined passage 25 which communicates withthe throttle barrel beyond the throttle.

lVith the idling adjustment needle valve 28 open, the suction producedby the depression from beyond the throttle, slightly modifie-d by theflow of air with fuel into the hole 24 atthe lower end of the by-passtube 22, is communicated to the fuel riser above the level. of theoverflow 8, and such depression in the fuel riser is further modifiedby-the vent 29 and may be adjusted or controlled by adjustment of theneedle valve 28,

Although the depression applied 111 the fuel riser during idling throughthe Inclined idling fuel passage 25 is modified by the hole 24 and thevent 29, the depression from beyond the throttle is very great so thatthe hole 24 which admits air from the air Intake 13 only slightlymodifies such depression and serves to admit fuel from the sump 23 intothe by-pass tube 22 from which it is delivered to beyond the throttle.Therefore, the fuel 'ad-' mitted' into the hole 24 serves to furtherreduce the modification of the depression in the by-pass tube 22.

Thus it will be seen that the correct portion of the depression frombeyond the throttle will be applied in the fuel riser 2 and drop pipe 3,the lower end of which during idling has been scaled as shown in Fig. 2.The vent 29 admitting air to the fuel riser above the level of theoverflow therein serves to supply 1 the necessary air to finally lowerthe depression in the fuel riser 2 and the sealed drop pipe 3 asufficient amount to cause the depression in such fuel riser 2 and droppipe 3 to cause the fuel in the riser to be liftedto the overflow point8 and to also act upon the surface of the fuel in the drop pipe 3 toretain a column of fuel therein which. may be subsequently used foraccelerating purposes when the throttle is opened and the depression Ktherein removed.

The constant level fuel chamber 1 will hold the-fuel level therein atthe normal height indicated'at. 30, and with the carburetor at rest, thefuel will be at the same height in the fuel riser, therefore, in idlingor under-load the depression at the top of the fuel riser must besuflicient to create the necessary delivery of fuel through the fuelorifice 7 and also to lift the fuel from the fuel level 30 to and overthe point of overflow 8 from whence such fuel flows by gravity throughthe fuel passage to the holes 12.

By adjustment of the vent 27 with the needle valve 28, a portion of thedepression beyond the throttle will be applied to provide the requisiteidling fuel and lift it over the overflow point 8. This adjustment,however, also accomplishes another purpose, viz, it provides for thenecessary accommulation of fuel in the drop pipe 3 of the fuel passage,

and the reservoir 11 for accelerating the engine from the lower speedsto the higher speeds and during idling it will accumulate fuel to fillthe reservoir 11 and the drop pipe 3 to a height Z). This isaccomplished because the first fuel flowing over the overflow 8accumulates in the seal pocket 10 and seals off the end of the seal tube9 which is below the level of the reservoir 11. Such seal prevents anybackward flow of air into the drop pipe 8, and immediately permits agreater depressionin the drop pipe 3 and the riser 2, which depressionis applied to the fuel orifice 7 and thereby increases the flow of fuelfrom the supply chamber until the new depression in the drop pipe 3 isbalanced by the weight of the column of fuel sustained therein. At thistime the reservoir 11 will have been filled and an equilibriumestablished at the normal idling speed, and fuel continuing to flowthrough the orifice 7, riser 2 over the overflow 8 to the top of thefuel at b in the drop pipe 3 will displace an equivalent amount throughthe fuel holes 12, and such displaced fuel will flow down the side ofthe member B to the sump 23 from which it will be delivered to above thethrottle through the idling by-pass 26 and the inclined passage 25. V

The height of the column of fuel sustained in the drop pipe 3constitutes a measure of pressure necessary to furnish the idling fuelthrough the orifice 7 and to lift such fuel over the overflow point 8.

Means are provided to allow air trapped in the reservoir from theprevious full load running position to escape so that the reservoir willbe filled with fuel when idling, and such means are shown as the vent 59leading from the top of the reservoir to some point near the throat ofthe venturi, or there may be provided a vent open to the atmosphere asshown by atmospheric air pipe 59' which is shown communicating betweenthe atmosphere in the air intake and the top of the reservoir through asmall vent 0 in the top of the pipe 59. The above described vents arefor the sole purpose of venting trapped air to permit the reservoir tofill.

As soon as the throttle is opened, the air vent 60 which leads from thetop of the reservoir into the jet holes 12 at a level corresponding tothat of the lower edge of said holes, will tend to allow any air stillremaining at the top of reservoir 11 or which may enter said reservoirin small quantities through the vent 59 or the pipe 59 to escape at jetholes 12 and to immediately break any surface tension at the dischargeends of said holes so that the fuelcollected in said reservoir will beejected in a direction away from the wall of the throat of the venturiat the first acceleration of fuel delivery.

Upon further opening of the throttle, the depression will greatlyincrease at the throat and draw more fuel in at 7, and more air mixedwith some fuel through the air vent 29, and cause the fuel held at thelevel 6 in the drop pipe 3 to be immediately discharged into thereservoir 11 simultaneously with the beginning of the discharge from thejet holes 12; and when the drop pipe 3 and seal tube 9 have been emptiedof solid fuel, the air coming from the fixed vent 29 will flow togetherwith fuel into the reservoir 11. The dam 54 in said reservoir 11 compelsthe fuel and air to flow in but one direction so that such air willgradually reach the various jet holes, one after the other. As thevelocity increases through the throat 6 of the venturi, there will befor any stable speed or velocity through the throat 6, a lesserdepression at the vent 29 than there is at the jet holes 12 so thatconsiderable air mixed with some fuel will flow through the vent 29 andthen flow with the fuel through the jet holes 12.

Ill)

The air vents 60 at the top of the reservoir are supplied with air fromthe fixed vent 59 and provide means whereby any and all air flowing withthe fuel will, under any load, be used to atomize the fuel at the jetholes 12. Each vent 60 is equal to or larger than the air vent c at thetop of the tube 59 so that the vent in tube 59 constitutes only a smallfactor in the amount of air which flows through the vent 60. Practicallyall of the air supplied to the vent 60 comes from the fixed vent 29except such minor portions as may come through the vent 27 from the airintake of the carburetor during load operation.

It is therefore seen that at all times all of the fuel is delivered tothe main air stream through one set of fuel jet holes, and that whenidling this fuel will fall downward from the jet holes at the throat ofthe venturi and be picked up by a bypass and ejected with greatatomizing force above the throttle, and during load operation a largevolume of air will at all times pass through the jet r holes 12 with thefuel and cause violent atom- 1 sure underneath the throttle above thethroat of the venturi to cause air to flow into the fuel passage fromthat point of higher pres sure and to circulate again through the throatof the venturi with the fuel emitted from the jet holes 12.

The starting plug 34 may be used not only for starting the carburetorinto action and to regulate a richer mixture while the motor is warmingup, but by adjusting the same by means of the adjusting screw 46 to ahigher position than that shown in full lines in Fig. 1, the area of theopening at the Venturi throat may be changed, to adapt the carburetorfor use with a smaller engine than when using the full opening of theVenturi throat, instead of having to change the Venturi throat.

The means shown in Figs. 3 and 4 for accumulation and delivery of fuelfor acceleration differs from those shown in Figs. 1, 2 and 8, in thatthe fuel passage from the drop pipe 3, seal tube 9 and seal pocket 10 isextended by groove 55 surrounding the fuel reservoir 56. In this casewhen idling, both the extension 55 of the fuel assage, and the reservoir56 will entirely 11 with fuel and upon opening the throttle toaccelerate the engine, fuel will be emptied out of the extension throughthe holes 57 in the same manner as from the reservoir 11, and as the airtel throat. In this case the riser 2 with the overflow point 8 and thedrop pipe 3 is practically the same as in the other figures. The fuelpassage is extended by tube 55 and performs a similar function to thatof groove 55 in Figs. 3 and 4, and delivers through the supply holes 57into the reservoir 56 and from such reservoir through the jet holes 12into the throat 6 of the venturi and in this way operates similar to theconstruction shown in Figs. 3 and 4.

I have discovered that by providing a pear shaped plug as at 34 it ispossible to so control the opening at the Venturi throat that uponstarting a cold motor and then adjusting the plug to get a smoothoperating condition with a richer mixture than normal, the proportionsof such mixture do not vary upon changing from no load operation to fullload operation and that I thereby avoid an unsatisfactory variationcommon to the operation with an ordinary butterfly choke. This isbecause of smooth stream line flow at the throat of the venturi whichhas been thus reduced instead of the violent eddies produced by theordinary starting choke, in fact this starting means acts in a manner asthough the size of the venturi had been reduced.

In ordinary conditions the plug can be set to give a little richermixture and will operate as though the mixture were set by adj ustingthe screw 52.

I claim:

1. A Venturi type carburetor provided with an air inlet and a mixtureoutlet; a throttle to control the mixture outlet; a fuel riser; a fuelorifice to admit fuel to the riser; a fuel passage adapted to conductfuel downward by overflow from the riser to the throat of the venturiand comprising a reservoir adapted to accumulate fuel at closedthrottle; a fixed port connecting the Venturi above the throat with theriser above the point of fuel overflow; a by-pass extending from the airintake to beyond the throttle and provided with a vent communicatingwith said riser above the point of fuel overflow; and a valve to controlsaid vent whereby the accumulation of fuel in said reservoir may becontrolled.

2. A Venturi type carburetor provided with an air inlet and a mixtureoutlet; at throttle to control the mixture outlet; a fuel riser; a fuelorifice to admit fuel to the riser;

a fuel passage adapted to conduct fuel clownward by overflow from theriser to the throat of, the venturi and comprising a reservoir adaptedto accumulate fuel at closed throttle; a fixed port connecting theventuri above the throat with the riser; means for applying to the riserabove the point of fuel overflow, a modified depression from beyond thethrottle and means for regulating the application of such depressionwhereby the accumulation of fuel in said reservoir may be controlled.

- 3. A Venturi type carburetor provided with an air intake; a mixtureoutlet; a constant level fuel supply chamber; a fuel riser; a fuelorifice connecting said riser and fuel supply chamber; a fuel passagereceiving fuel by overflow from said riser andadapted to conduct fuel tothe throat of the venturi, said fuel passage being expanded at its lowerend to constitute a reservoir surrounding the throat of the venturi; andjet holes leading upward from the bottom of said reservoir and stantlevel fuel supply chamber; a fuel riser;

a fuel orifice connecting said riser and fuel supply chamber; a fuelpassage receiving fuel by overflow from said riser and adapted toconduct fuel to the throat of the venturi, said fuel passage beingexpanded at its lower end to constitute a reservoir surrounding thethroat of the venturi; jet holes leading upward from the bottom of saidreservoir and open to the throat of the venturi; and air ventsrespectively communicating with the top of the reservoir and with thedischarge end of each jet hole.

5. A carburetor having an air inlet; amix ture outlet; and a mixingchamber in the form of a Venturi tube; a throttle in the mixture outlet;a constant level fuel chamber; a suction chamber; a riser opening intosaid suction chamber and supplied with fuel from said constant levelfuel chamber; a drop-pipe receiving fuel by overflow from said riser anddischarging said fuel into the main air stream adjacent the Venturithroat; means for admitting the depression above the throttle to thesuction chamber; and means for admitting the depression underneath thethrottle direct into the suction chamber to modify the depressionadmitted to the suction chamber from above the throttle.

6. A Venturi type carburetor provided with a Venturi throat and a fuelriser; a fuel orifice to admit fuel to said riser, and a droppipe toconduct fuel downward by gravity from said riser to said Venturi throat;and

means whereby fuel may be drawn through the fuel orifice over the top ofthe fuel riser under the depression imposed by the air velocity throughthe venturi as applied at the throat of the venturi, modified by thedepression immediately under the throttle during a Venturi throat andthrottle and a fuel riser,

means to supply fuel to the riser, a droppipe into which fuel overflowsfrom the riser; means to apply a depression in the riser and drop-pipe;a reservoir surrounding the venturi throat and into which fuel from thedrop pipe may accumulate during idling, means connecting said reservoirwith the venturi throat; and means whereby the fuel accumulated in saidreservoir will be delivered to the Venturi throat upon opening thethrottle.

8. A carburetor having a Venturi tube, a throttle and a constant levelfuel chamber, a fuel passage, a fuel orifice to admit fuel to said fuelpassage from said. fuel chamber, said fuel passage being provided with areservoir and also extended to surround the Venturi tube, said reservoirbeing provided with supply holes opening from said extended portion atthe bottom thereof and arranged to fill the reservoir, said reservoir being provided at its top opposite said supply holes with et holesdischarging into the Venturi tube from the top of the reservoir,

so that upon opening the throttle, such extension will be emptiedthrough the reservoir in such a manner as to gradually empty theextension.

, 9. A Venturi type carburetor provided with a reservoir around theVenturi throat and communicating with the throat through jet holesextending upwardly from the bottom of the reservoir to a point levelwith the top thereof where they communicate with the Venturi throatbelow the normal fuel level, said reservoir constituting a portion of afuel passage supplied with fuel through overflow from a fuel riser andwith air from the expanding portion of the venturi underneath thethrottle.

10. A Venturi type carburetor provided with a reservoir in anapproximately horizontal plane around the Venturi throat andcommunicating with the throat through jet holes extending upwardly fromthe bottom of the reservoir to a point level with the top thereof wherethey communicate with the Venturi throat below the normal fuel level,said res ervoir constituting a portion of a fuel passage supplied withfuel through overflow from a fuel riser and with air from the ex pandingportion of the venturi underneath the throttle, said reservoir being soadapted and arranged that fuel and air will flow in but one directionalong the same.

11. A Venturitype carburetor provided with a reservoir around theVenturi throat and communicating with the throat through j et holesextending upwardlyfrom the bottom of the reservoir to a point level withthe top thereof where they communicate with.

the Venturi throat, said reservoir constitut ing a portion of a fuelpassage supplied with fuel through overflow from a fuel riser and withair from the expanding portion of the Venturi underneath the throttle;said reservoir being provided with means to form a seal pocket where thereservoir receives fuel.

12. A Venturi type carburetor having a .fuel riser; means to supply fuelto said riser; an annular reservoir surrounding the throat of theventuri; jet holes connecting said res-,

ervoir to the main air stream at the throat of the Venturi a sealingpocket in the reservoir; and a drop-pipe communicating at its upper end.with said fuel riser and having its lower end extended into said sealingpocket.

18. A carburetor having a Venturi tube; an

I air inlet and a mixture outlet; a constant level fuel supply chamber;a fuel passage adapted to deliver fuel from said fuel supply chamher tothe main air stream at the Venturi throat and comprising a reservoir;and means in said reservoir to form a seal pocket where the reservoirreceives fuel.

14. A Venturi type carburetor provided with a fuel passage fordelivering fuel to the main air stream at the Venturi throat under allconditions of operation; and provided with idling adjusting meanscomprising an idling by-pass adapted and arranged to deliver fuel, aftersuch fuel has been delivered to the main air stream, to beyond thethrottle, said by-pass tube being fitted with an adjustable vent open tosaid fuel passage.

15. A carburetor provided with a Venturi tube, a throttle and an airintake; a fuel passage adapted to deliver fuel to the main air stream atthe Venturi throat; a sump in the air intake adapted to accumulate fuelfrom the fuel passage; and a by-pass open to said fuel passageintermediate its ends and adapted to deliver fuel accumulated in saidsump to beyond the throttle.

16. A Venturi type carburetor provided with a throttle barrel, athrottle and a fuel passage adapted to conduct fuel to the main airstream at the throat of the Venturi; a fixed port communicating betweensaid fuel passage and the throttle barrel below the throttle; a valvecontrolled vent extending from beyond the throttle to said fuel passage;a reservoir arranged to accumulate fuel from said fuel passage undercontrol of the valved vent at closed throttle; upwardly extending jetholes communicating from the bottom of said reservoir to the throat ofthe Venturi so as to empty the reservoir under suction, and a ventcommunicating between the top of the reservoir and the atmosphere toprevent trapping of air in said reservoir.

17. A Venturi type carburetor provided with a throttle bore, a throttleand a fuel passage adapted to conduct fuel to the main air stream at thethroat of the Venturi; a fixed port communicating between said fuelpassage and the throttle barrel below the throttle a valve controlledvent extending from beyond the throttle to said fuel passage; areservoir arranged to accumulate fuel from said fuel passage undercontrol of the valved vent at closed throttle; upwardly extending jetholes communicating from the bottom of said reservoir to the throat ofthe Venturi so as to empty the reservoir under suction, and a ventcommunicating between the top of the reservoir and the Venturi.

18. A Venturi type carburetor provided with a throttle bore, a throttleand a fuel passage adapted to conduct fuel to the main air stream at thethroat of the Venturi; a fixed port communicating between said fuel passage and the throttle barrel below the throttle a valve controlled ventextending from be yond the throttle to said fuel passage; a reservoirarranged to accumulate fuel from said fuel passage under control of thevalved vent at closed throttle; upwardly extending jet holescommunicating from the bottom of said reservoir to the throat of theVenturi so as to empty the reservoir under suction, a vent communicatingbetween the top of the reservoir and the atmosphere; and a ventcommunicating between the top of the reservoir and the Venturi.

In testimony whereof, I have hereunto set my hand at Los Angeles,California, this 8th day of April, 1922.

ORVILLE H. ENSIGN.

